7c44b600f
Denys Vlasenko
2018-01-17
Subject
udhcpc[6]: remove overzealous timeout clamping code
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networking/udhcp/d6_dhcpc.c+6 -11
| @@ -1465,8 +1465,8 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv) | |
| if (packet.d6_msg_type == D6_MSG_REPLY) { | |
| uint32_t lease_seconds; | |
| struct d6_option *option; | |
| - | int address_timeout; |
| - | int prefix_timeout; |
| + | unsigned address_timeout; |
| + | unsigned prefix_timeout; |
| type_is_ok: | |
| address_timeout = 0; | |
| prefix_timeout = 0; | |
| @@ -1626,12 +1626,9 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv) | |
| move_from_unaligned32(lease_seconds, iaaddr->data + 16 + 4); | |
| lease_seconds = ntohl(lease_seconds); | |
| /// TODO: check for 0 lease time? | |
| - | /* paranoia: must not be prone to overflows */ |
| - | if (lease_seconds > 0x7fffffff / 1000) |
| - | lease_seconds = 0x7fffffff / 1000; |
| - | address_timeout = lease_seconds / 2; |
| bb_error_msg("%s obtained, lease time %u", | |
| "IPv6", /*inet_ntoa(temp_addr),*/ (unsigned)lease_seconds); | |
| + | address_timeout = lease_seconds; |
| } | |
| if (option_mask32 & OPT_d) { | |
| struct d6_option *iaprefix; | |
| @@ -1662,18 +1659,16 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv) | |
| } | |
| move_from_unaligned32(lease_seconds, iaprefix->data + 4); | |
| lease_seconds = ntohl(lease_seconds); | |
| - | /* paranoia: must not be prone to overflows */ |
| - | if (lease_seconds > 0x7fffffff / 1000) |
| - | lease_seconds = 0x7fffffff / 1000; |
| - | prefix_timeout = lease_seconds / 2; |
| bb_error_msg("%s obtained, lease time %u", | |
| "prefix", /*inet_ntoa(temp_addr),*/ (unsigned)lease_seconds); | |
| + | prefix_timeout = lease_seconds; |
| } | |
| if (!address_timeout) | |
| address_timeout = prefix_timeout; | |
| if (!prefix_timeout) | |
| prefix_timeout = address_timeout; | |
| - | timeout = address_timeout > prefix_timeout ? prefix_timeout : address_timeout; |
| + | /* note: "int timeout" will not overflow even with 0xffffffff inputs here: */ |
| + | timeout = (prefix_timeout < address_timeout ? prefix_timeout : address_timeout) / 2; |
| /* paranoia: must not be too small */ | |
| if (timeout < 0x10) | |
| timeout = 0x10; | |
networking/udhcp/dhcpc.c+4 -2
| @@ -1732,8 +1732,10 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv) | |
| /* paranoia: must not be too small and not prone to overflows */ | |
| if (lease_seconds < 0x10) | |
| lease_seconds = 0x10; | |
| - | if (lease_seconds > 0x7fffffff / 1000) |
| - | lease_seconds = 0x7fffffff / 1000; |
| + | //if (lease_seconds > 0x7fffffff) |
| + | // lease_seconds = 0x7fffffff; |
| + | //^^^not necessary since "timeout = lease_seconds / 2" |
| + | //does not overflow even for 0xffffffff. |
| } | |
| #if ENABLE_FEATURE_UDHCPC_ARPING | |
| if (opt & OPT_a) { | |